最近給公司的一個iOS項目進行組件化解耦。本身項目早期開發就不是很規范，而且剛剛開始熟悉這個項目對業務方面也不是很熟悉所以並沒有對所有的模塊進行組件化。而且組件化解耦後還存在一些問題在文章中都會寫出來。
原理和蘑菇街 App 的組件化之路類似，但是也有一些不同並沒有加入「組件A」要調用「組件B」的某個方法這種業務場景。所有組件化的模塊都是「組件A」要調用「組件B」的這種情況。「組件A」與「組件B」之間是透明的。

為何要對項目組件化

首先說一下組件化帶來的最大好處就是給每個模塊間解耦。之前模塊間調用不得不相互引用，這就導致了各個模塊間相互依賴。想象一種場景：A，B，C，D是四個VC，四個VC之間是這樣的關系，A與B相互跳轉、B與C相互跳轉、D與A，B相互跳轉。它們之間的關系如下圖：

而組件化在項目中引入了Mediator對象與Action對象，引入這兩個對象後，A，B，C，D之間的關系如下圖：

<喎?/kf/ware/vc/" target="_blank" class="keylink">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"組件化方案的實現">組件化方案的實現

通過程序啟動時注冊URL來實現組件化，URL注冊用通過JLRoutes實現的。
具體使用如下：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    JLRoutes *routes = [JLRoutes routesForScheme:scheme_url];

    [routes addRoute: LSYKey1 handler:^BOOL(NSDictionary * _Nonnull parameters) {
        //要處理的邏輯
        return YES; //判斷返回值來決定是否執行該處代碼
    }];
}

-(BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation   //當程序嘗試打開URL或者處理完從其它應用返回時會調用該方法 (不同版本的系統需要實現的方法不同)
{   
    if ([url.scheme isEqualToString:scheme_url]) {
       return  [JLRoutes routeURL:url];
    }
    return YES;
}

    JLRoutes *routes = [JLRoutes routesForScheme:scheme_url];

    [routes addRoute: LSYKey1 handler:^BOOL(NSDictionary * _Nonnull parameters) {
        NSInteger oid = [parameters[@"oid"] integerValue]; //獲取url中oid參數
        NSInteger amount = [parameters[@"amount"] integerValue]; //獲取url中amount參數

        return YES; 
    }];

#import 

static NSString * const LSYKey1 = @"LSYKey1";

static NSString * const LSYKey2 = @"LSYKey2";

static NSString * const LSYKey3 = @"LSYKey3";

...

#import 

@interface Mediator : NSObject

/**
 JLRountes注冊的url
 */
+(void)componentRegister;

/**
 本地通過key打開模塊

 @param key 模塊key
 @param dic 傳遞的參數
 */
+(void)openComponentForKey:(NSString *)key parameter:(NSDictionary *)dic;

/**
 該方法通過運行時的機制讓Mediator對象與Action對象解耦並將消息轉發給Action對象執行

 @param targetName Action對象名
 @param actionName 方法名
 @param params     傳遞的參數
 */
+(void)performTarget:(NSString *)targetName action:(NSString *)actionName params:(NSDictionary *)params;
@end

@implementation Mediator


+(void)componentRegister
{
    JLRoutes *routes = [JLRoutes routesForScheme:scheme_url];

    [routes addRoute: LSYKey1 handler:^BOOL(NSDictionary * _Nonnull parameters) {
        [self performTarget:@"Action" action:@"performActionA" params:parameters];
        return YES;
    }];

        [routes addRoute: LSYKey2 handler:^BOOL(NSDictionary * _Nonnull parameters) {
        [self performTarget:@"Action" action:@"performActionB" params:parameters];
        return YES;
    }];


}
+(void)openComponentForKey:(NSString *)key parameter:(NSDictionary *)dic
{
    //將本地調用傳入的Key與參數轉拼接成url最後通過JLRoutes處理
    if (!key.length) {
        return;
    }
    NSMutableString *urlString = [NSMutableString stringWithString:[NSString stringWithFormat:@"%@://%@",scheme_url,key]];
    [urlString appendString:@"?"];
    [dic enumerateKeysAndObjectsUsingBlock:^(id  _Nonnull key, id  _Nonnull obj, BOOL * _Nonnull stop) {
        [urlString appendString:[NSString stringWithFormat:@"%@=%@&",key,obj]];
    }];
    [urlString deleteCharactersInRange:NSMakeRange(urlString.length-1, 1)];
    NSURL *url = [NSURL URLWithString:[urlString copy]];
    [JLRoutes routeURL:url];
}

+(void)performTarget:(NSString *)targetName action:(NSString *)actionName params:(NSDictionary *)params
{
    NSString *targetClassString = [NSString stringWithFormat:@"%@", targetName];
    NSString *actionString = [NSString stringWithFormat:@"%@:", actionName];

    Class targetClass = NSClassFromString(targetClassString);
    id target = [[targetClass alloc] init];
    SEL action = NSSelectorFromString(actionString);

    if ([target respondsToSelector:action]) {
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Warc-performSelector-leaks"
         [target performSelector:action withObject:params];
#pragma clang diagnostic pop
    } else {
        // 這裡是處理無響應請求的地方

        }
    }
}
@end

#import "Action+Jump.h"

@implementation Action (Jump)
-(void)performActionA:(NSDictionary *)params
{
    //跳轉A界面
}
-(void)performActionB:(NSDictionary *)params
{
    //跳轉B界面
}
@end

[Mediator openComponentForKey:LSYKey1 parameter:@{@"oid":@123,@"amount":@"456"}];

    [JLRoutes routeURL:url];

    [Mediator componentRegister];